The Cutting Edge of Compost Research Kathy Doesken and Addy Elliott Department of Soil and Crop Sciences Colorado State University
Introduction Compost markets are growing and research will help speed up this process Nation wide research exists but is important to asses its applicability for our region CSU started compost research in 2000 Unlike fertilizer research that is supported by BIG $$$, compost research receives little support.
Research Update #1 Title: Organic Matter and Nitrogen Conservation in Manure Compost for Organic Agriculture Authors: Raviv, M., S. Medina, A. Krasnovsky, and H. Ziadna Reference: Compost Science and Utilization. Winter 2004. 6-10. http://www.jgpress.com/compost.htm
#1 Organic Matter and Nitrogen Conservation - Background In aerobic composting an average of 40% of initial N is lost. Main factors leading to ammonia volatilization are: Initially low C:N ratio (low N immobilization) High ph materials (low ammonium solubility) High oxygenation rate (low aeration = less volatilization) High temperature in thermophilic stage (lower temps = slower conversion of organic matter)
#1 Organic Matter and Nitrogen Conservation - Objectives To maximize nitrogen (N) and organic matter (OM) levels in compost made from agricultural wastes Specifically: minimize N loss and manage compost windrows at moderate temperatures
#1 Organic Matter and Nitrogen Conservation - Methods 3 carbon materials added to separated cow manure Grape marc, 1:1 volumetric Orange peels, 1:1 volumetric Wheat straw, 2:1 volumetric Forced aeration by pipes (2 min/hour) Temp. kept @ 131 F at 40 cm (15.8 in) depth Moisture kept @50-60% during thermophilic and 40-50% afterwards (through 140 days) Piles turned 2 times with front end loader
#1 Organic Matter and Nitrogen Conservation - Methods N availability and release potential were testing by growing cherry tomatoes in buckets with these mixes: Peat/ guano mix (fertilizer control ) Peat only (control) Raw and Composted manure/grape marc mixes Raw and Composted manure/orange peel mixes Raw and Composted manure/wheat straw mixes Irrigated based on ET and drainage collected from pots (drained water tested for N) Tests conducted: Quantity of discharged water, chemical analysis of drained water/2 weeks, plant height, # trusses and # of fruits >7mm.
#1 Organic Matter and Nitrogen Conservation - Results Manure/orange peel compost contained highest % N Manure/grape marc had least plant available N (high total N concentration but mostly immobilized) Manure/wheat straw had lowest total N but highest plant available N All three composts had higher N conservation rates (92%) than the average composts cited in the literature
#1 Organic Matter and Nitrogen Conservation - Results
#1 Organic Matter and Nitrogen Conservation - Results Manure/wheat straw and manure/orange peels had highest yields and largest plant size. No yield differences were measured among pots with either M/wheat straw or M/orange peels compared to both treatments plus guano. Therefore, the N needs of the tomatoes were met by compost alone. Addition of carbonaceous (small enough particle size for microbial digestion) and/or acidic additives to cow manure, under moderate temperatures can result in higher N and OM than other composts.
#1 Organic Matter and Nitrogen Conservation - Application Compost piles made with average 40:1 C/N ratios result in compost with greater N conservation. Compost piles made with lower ph materials conserve N. Compost piles managed at average 130 F conserve organic matter.
Research Update #2 Title: Soil Properties as Influenced by Phosphorus- and Nitrogen-Based Manure and Compost Applications Authors: Bahman Eghball Reference: Agronomy Journal. 94: 128-135. 2002. http://agron.scijournals.org/
#2 Soil Properties - Introduction Compost applied to meet N needs of a crop provides more P to the soil than a crop can take up. Beef feedlot manure contains about 15% carbon (C) that can be used to improve soil physical and chemical properties. Increasing soil organic matter increases the soils water holding capacity, nutrient holding capacity, infiltration rate, and decreases its runoff potential.
#2 Soil Properties - Objectives To evaluate the effects of application frequency and N- and P-based applications of composted and non-composted manure on the following soil properties: Carbon Nitrogen (total N, nitrate, ammonium) ph EC (electrical conductivity = soluble salts) Soil bulk density
#2 Soil Properties - Methods 1992-1996, Nebraska, silt clay loam, dryland field Rainfall rates: 1993-30 inches 1994-21 inches 1995-12 inches 1996-17 inches
#2 Soil Properties - Methods Composted and non-composted beef manure applied annually or biennially then disked within 2 days Application rate based on N or P removal by corn crop Inorganically fertilized field and control field also planted Assumptions: N mineralization rate: year 1 =20%, year2 =20%, year 3 =10%, year 4 = 5% P mineralization rate: year 1 =60%, year2 =20%, year 3 =10%, year 4 = 10% All nutrient mineralization rates change based on soil moisture, temperature, and organic matter
#2 Soil Properties - Results Biennial N based compost treatment had greater carbon and nitrogen concentrations in top 0-6 inches, even though similar total amounts were applied About 25% of applied manure C remained in the soil after 4 years of application About 36% of applied compost C remained in the soil after 4 years of application even though cumulative C application rate during 4 year study was less for compost
#2 Soil Properties - Results EC increased more with annual and biennial N-based manure and compost compared with P-based application rates Surface P concentrations were greater for N-based compost and manure applications, indicating the P accumulation occurs with N- based application Fertilizer application resulted in greater nitrate than manure or compost in dry years
#2 Soil Properties - Application Heavier biennial compost applications may protect C and N from mineralization, compared with smaller annual rates Carbon deposition into soil is greater from compost application compared to manure N-based application rates lead to increased soil P This poses a pollution hazard to surface water as P may leave the field during a runoff event Nitrate accumulation from fertilizer might be greater than manure and compost in dry years
Research Update #3 Title: Compost Application Effects on Turf Production Authors: Grant Johnson, M.S. Reference: in review http://www.colostate.edu/depts/soilcrop/extension/soils/index.ht ml
#3 Turf - Introduction In Colorado, high concentrations of nitrogen and phosphorus are contaminating the water along the South Platte River. Years of drought have increased city water use for turf management
#3 Turf - Objectives To determine if topdressing composted dairy manure on turf grass will: Increase drought tolerance of turf Increase infiltration of water Decrease runoff of nitrogen and phosphorus from turf Increase clipping yield
#3 Turf - Methods Applied compost to plots at following rates: 0 ft 3 /acre, 472 ft 3 /acre, 944 ft 3 /acre, 1416 ft 3 /acre Measured turf temperature at soil surface Simulated rainfall above plots and collected runoff water to analyze for nutrients Measured biomass production for each turf plot
#3 Turf - Results Compost treatments maintained quality longer into the fall, while increasing green up in the spring. The two highest compost rates increased volumetric soil water content during dry down periods, which helped lower canopy temperatures as well. Runoff collected in rainfall event met the EPA standards for dissolved nitrates and phosphates. Nitrate leaching was not significant in any of the treatments.
#3 Turf - Application Top dressing compost led to a longer production season for turf compared to control plots with no compost 944 ft 3 /acre and 1416 ft 3 /acre application rates increased time between irrigation 944 ft 3 /acre and 1416 ft 3 /acre application rates decreased canopy temperature, resulting in less drought-stress Runoff from turf top dressed with compost (at these rates) did not pose threat to surface water quality
Research Update #4 Title: IMPACT OF ORGANIC PHOSPHORUS SOURCES ON PHOSPHORUS RUNOFF Authors: Elliott, A.L., J.G. Davis Reference: in review http://www.colostate.edu/depts/soilcrop/extension/soils/index.html
#4 Source Effects on P Runoff- Intro Eutrophication" is water pollution caused by excessive plant nutrients. Phosphorus is more easily controlled since plants cannot assimilate it from the air (like N from the atmosphere) Limited research exists on phosphorus sources and their potential for runoff from alkaline, calcareous soils
#4 Source Effects on P Runoff- Objectives The objective of this study was to distinguish between P sources and their potential to release P into runoff. Investigate the runoff, both chemically and physically, from agricultural plots that were amended with raw dairy manure, composted dairy manure, and vermicomposted dairy manure.
#4 Source Effects on P Runoff- Methods Four P sources were applied in the spring of year 1 as raw manure, compost and vermicompost from Dyecrest Dairy manure and rock phosphate (<0.02 mm 2). Applied at 80 and 160 lbs. P 2 O 5 /acre Tilled immediately Simulated rainfall in spring of year 1 and year 2 (collected runoff water and sediment) Planted cucumber and tested tissue for P
#4 Source Effects on P Runoff- Results The high rate raw manure treatment resulted in significantly higher total dissolved P values in 2002 and 2003. The vermicompost treatment produced less overall P runoff than the raw manure and compost treatments. Compost and vermicompost that have been applied at the same P 2 O 5 rate as raw manure have significantly less runoff P available than raw manure. Rock P was not soluble in this alkaline soil.
#4 Source Effects on P Runoff- Application Raw manure applications result in a higher concentration of polluting P than does application of compost or vermicompost applied at the same lb/acre rate Rock phosphate is not a good product to use in soils with a ph greater than 7.0
Research Update # 5 Title: Compost Teas: Microbial Hygiene and Quality In Relation to Method of Preparation Authors: W. Brinton, P. Storms, E Evans, J. Hill (Woods End Lab) Reference: Journal of Biodynamics, Summer, 2004.
# 5 Compost Teas: Background Information Compost tea is a value added product made from compost with income potential It is a liquid made with a small amount of high quality compost and water Numerous methods of making tea exist Commercial tea brewers usually involve aeration and adding nutrients Little research available about teas; some research suggests E. coli multiplies in teas
# 5 Compost Teas: Objectives To evaluate whether 2 commercial tea brewing systems could present pathogen risk when used as directed To measure microbial growth in various teas by monitoring plate counts for aerobic and anaerobic bacteria, fungal counts, and E. coli To compare the effects of mechanical aeration (commercial systems) or lack of aeration ( European system) on microbial counts and dissolved oxygen in the teas
# 5 Compost Teas: Methods Experiment 1 (first week) 2 commercial extractors that provided constant bubbling aeration used to make compost tea Both using proprietary composts and nutrient additives one nutrient additive contained nutrients plus molasses one nutrient additive contained nutrients and no molasses, which may support rapid growth of E.coli European method used with no nutrient additives or aeration solution stirred once daily for
# 5 Compost Teas: Methods, continued Experiment 2 (second week) experiment was repeated but teas were inoculated with 1 ml 10 8 E. coli at time 0 to see if it would multiply Experiment 3 (third week) Experiment repeated but teas were made using immature compost to test what would happen if home-made low quality compost was used in the commercial brewer instead of what came with the brewer
# 5 Compost Teas: Methods Sampling Teas were sampled at the following times Time = 0 (immediately after start of tea brewing) Time = 24 hours Time = 48 hours Time = 72 hours Analysis at Woods End Labs E. coli using most probably number technique Aerobic bacteria (aerobic plate count) Anaerobic bacteria (anaerobic plate count) Total viable fungi (fungal plate count)
# 5 Compost Teas: Results No E. coli found at time 0 in commercial teas or European tea (seed compost clean) No increase of E. coli at time 24 Both commercial teas spiked with E. coli were able to support its growth (both with and without addition of molasses) E. coli added in all 3 brewing systems increased at T 24 and declined after 72 hours
# 5 Compost Teas, results, continued Both commercially brewed teas showed more aerobic bacteria counts after three days standing than after 24 hours of mechanical aeration. Aerobic bacteria increased in European tea without mechanical aeration Results support European view that longer extraction times without continuous mechanical aeration make good quality teas
#5 Compost Teas: Conclusions Short-term commercially brewed teas (24 hours) with molasses added may be least safe practice because E. coli decreased at T 72 in all teas in these experiments Avoid introduction of unwanted microbes by proper cleaning of brewing equipment and by choosing uncontaminated high quality compost. If brewing outside, cover to prevent bird droppings, etc. from contaminating brewing teas Compost teas promising value added compost product! More research needed.
Research Update # 6 Title: Environmental Effects of Applying Composted Organics to New Highway Embankments: Part 1. Interrill runoff erosion. Authors: Persyn, R.A.; Glanville, T.D.; Richard, T.L.; Lafien, J.M.; Dixon, P.M. Reference: Transactions of the ASAE. Vol. 47, no. 2, pp. 463-469/<ar/-Apr. 2004 Web: http://www.asae.org/pubs/fulltext.html
# 6 Background Information: Road construction creates disturbed soils which lack topsoil and erode easily causing water quality problems Good vegetation establishment controls erosions Compost can help establish vegetation and cause favorable changes in a soio s physical qualities Potential market in Colorado for more compost usage in roadside vegetation Potential for other value-added compost products http://www.urbannature.org/waste/txtdot_compost.htm
# 6 Compost on Highways: Objectives To evaluate the use of composts applied as mulch blankets to decrease runoff and erosion
# 6 Compost on Highways: Methods Composts made from biosolids, yard waste, and bio-industrial byproducts were applied to both compacted subsoil and imported topsoil on a 3:1 slope on a highway embankment
#6 Compost on Highways: Methods Composts were applied 5 &10 cm (2 and 4 inches) deep over compacted subsoil Topsoil was applied 15 cm (6 inches) deep over compacted subsoil Rainfall at 95 mm (3.7 inches) per hour was applied with a rainfall simulator to both soils Runoff was collected for 1 hour after runoff began Sediment load in runoff samples measured
Rainfall Simulator
# 6 Compost on Highways: Results All compost treatments were effective at reducing erosion rates under simulated rainfall All three composts required 30 minutes or longer to produce runoff On both compacted subsoil and 15 cm of topsoil over compacted subsoil runoff occurred after 8 minutes
#6 Compost on Highways: Conclusions Compost is an effective soil treatment for controling erosion on newly planted highway embankments
#6 Compost on Highways: Applications Some research done with quantifiable results; Colorado currently using some compost on highway revegetation States doing research with compost on highways: Connecticut, Texas, Iowa (others?) Challenges in CO: education, selling the right quality compost for roadside revegetation Value-added products? Berms to replace silt fences (Biocycle, May 2001)
Research Update # 7 Title: Cumulative Effect of Leaf Compost on Yield and Size Distribution in Onions Authors: Abigail A. Maynard, David E. Hill Reference: Compost Science and Utilization, Vol. 8, No. 1, pp. 12-18. 2000. http://www.jgpress.com/compost.htm
#7 Compost & Onions: Background 2001 CO Agricultural Statistics: Colorado 5 th in nation in acres of onions grown 12,000 acres grown, 10,000 in eastern CO Valued at $43,152,000 http://pestdata.ncsu.e du/cropprofiles/docs/c oonions.html
#7 Onions & Compost: Methods Field experiment conducted at the Connecticut Agricultural Experiment Station s Valley Laboratory on a sandy loam. A 20 x 40 plot was divided into 2 20 x 20 plots. In 1996,97, & 98 a one inch layer of leaf compost (50 T/A) was surface applied and tilled in to the same subplot plot of the paired plots About 1 month later 4 cultivars of onions were transplanted into each of 20 x 20 subplots, 3 reps
# 7 Onions & Compost: Methods 2 Fertilizer (10-10-10) was added each year prior to planting at.7 T/A Note: Herbicides and pesticides were used as needed this was not an attempt at growing onions organically
#7 Onions & Compost: Results Yield of 4 cultivars grown on compost amended soil varied 3% (574-598 50 lb bags/a) Yield of 4 cultivars grown without compost varied 52% (419-638 50 lb bags/a) Yield decrease due to soft rot decreased in year 3 Leaf compost high in microbial diversity may have been a factor in disease suppression
#7 Onions & Compost: Results 2 Cultivars most susceptible to soft rot diseases more responsive to compost amendments than cultivars with higher resistance to soft rot diseases Cumulative effect of compost amendment: yields of most onion cultivars increased after more than one year of compost applications
#7 Compost and Onions 12,000 acres of onions grown in Colorado in 2001 Potential for compost use by onion growers?
#8 Compost Research at Colorado State University
2000: Compost and Apples Funded by a small WSARE grant, Dr. Jessica Davis and orchard owner Steve Ela coordinated to evaluate the impact of chicken manure and compost applications to the soil of 2 apple orchards http://www.sare.org/reporting/report_vie wer.asp?pn=fw00-032&ry=2004&rf=1
Methods: Apples and Compost Chicken manure was applied at 5 and 10 T/A to 2 orchards in western CO Compost was applied at 0.5 and 1 T/A to same 2 orchards Soils were sampled in each orchard and analyzed
Results: Apples and Compost Over 2 years, with annual treatments, soil fertility generally increased in both orchards In the second year, compost and manure had no effect on microbial biomass or total meters of fungus Manure reduced ph (a good thing in CO) and increased salinity (a not-so-good-thing) Manure increased OM 2% Compost increased salinity???
Compost and Apples: Conclusions (?) Compost and Apples was first compost research Compost not analyzed we didn t characterize (analyze) the compost We have learned a lot about conducting compost research in 5 years: big lesson is characterize composts and manure to be studied Study should be redone with compost and manure that have been tested Redo research and increase compost rates?
Making Compost from CSU Wastes 2003: The Diagnostic Lab at CSU s Vet Hospital uses an alkaline digester to treat carcasses Liquid industrial by-product produced by digester can t go to waste water treatment plant; can t go to landfill C:N of liquid is 6:1, no pathogens, no heavy metals
Making Compost from CSU Wastes CSU Equine Teaching and Research Center generates stable waste (wood shavings and horse manure) and horse manure from horses kept in both stalls and corrals January 2003 feasibility study of composting industrial by-product with stable wastes composted well
Digester Spooge Compost Feasibility Study, Compost and Air Temperature over Time, January 1-19, 2004 160.0 140.0 120.0 spooge added, pile turned spooge incorporated, pile turned Temperature (Deg. F) 100.0 80.0 60.0 40.0 20.0 0.0-20.0 12/30 12/31 1/1 Compost Windrow Built 1/2 1/3 1/4 1/5 1/6 1/7 1/8 1/9 1/10 Date 1/11 1/12 1/13 1/14 1/15 1/16 1/17 1/18 1/19 Max Air Temp. Min Air Temp. Actual mean Compost Compost + Data collected and results prepared by Kathy Doesken. Air temperature from Christman
Making Compost from CSU Wastes August 2004 present Research ongoing to produce good quality compost from CSU wastes that can be used on campus
Making Compost from CSU Wastes Progress Compost made from September 2004 present Compost evaluations showed no significant differences between compost from 5 different feedstocks, and C:N 38:1 (higher that class I or II compost) ph, EC of all composts in Class I or II Compost will be tested as a surface mulch around perennials
Making Compost from CSU Wastes Second set of feedstock mixes planned for summer 2005 Goal to reduce C:N in final compost Increase proportion of liquid digester waste Try different bedding options: pelleted wood? Student research project to look at bedding options
Compost on Forages Objectives Develop guidelines for CO for growing organic grass horse hay Evaluate compost tea on forages Possibly include alfalfa which is planted next to grass pasture Evaluate effect of compost manure, and commercial fertilizer on forage quality as well as yields
Compost on Forages Spring 2004: Grass pasture mix planted at CSU research farm near Fort Collins Fall 2004: Compost made from horse manure, bulking agents Fall 2005: compost application for 2006 season Urea in spring 2006 Compost fall 2005 Compost tea: throughout 2006 season
Kathy Doesken and Adriane Elliott, Soil and Crop Sciences Dep Colorado State University 970-491-6984 www.manuremanagement.info